<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- 创建promise的实例 -->
   <script>
   const p1 = new Promise(()=>{
        console.log('开始请求a');
        // 定时模拟ajax
        setTimeout(()=>{
            console.log('请求a结束');
        },3000)
   })
   console.log(p1);
   console.log(1);
   </script>
</body>
</html>